Portion of lock



FIG. 1 is a front view of a portion of lock showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a rear view thereof.

The broken lines shown in FIGS. 2-6 represent environmental subject matter and form no part of the claimed design. 

The ornamental design for a portion of lock, as shown and described. 